Searching for lost items has been a problem for millennia. For example, dozens of patents have described methods for seeking to retrieve a temporarily lost golf ball.
Horchler U.S. Pat. No. 3,782,730 uses a magnetically actuated switch to turn on or off a radio oscillator at the core of the golf ball, whose radio signal can be monitored by the player whenever the ball is temporarily lost.
Engimeier U.S. Pat. No. 5,423,439 employs a rechargeable battery and a system for electromagnetically transmitting energy to the battery charger of a Horchler type of golf ball.
Little U.S. Pat. No. 5,626,531 employs a capacitance system which tags such ball whenever activated by the radiation from a Horchler-type of target-seeking monitor.
Kroll et al U.S. Pat. No. 5,662,534 also uses a monitor sending out a series of pulses of radio beams, and analyzing the reflected radio waves. In Kroll et al, the golf ball features a generic reflector of such radio beams.
Valintino U.S. Pat. No. 5,132,622 employs a golf ball having a metal center and the combination of a metal detector and target-seeking scoop to retrieve a lost golf ball.
Chadwell U.S. Pat. No. 6,552,433 seeks to locate a golf ball by metal detection and/or Radar, suggesting several modifications, some designed to measure the distance to the lost golf ball.
Barnhill U.S. Pat. No. 5,112,055 prepares a spherical golf ball, and then creates a cavity in which a signal-generator is installed that is activated by the hitting of the ball.
Kuesters U.S. Pat. No. 6,113,504 provides a golf course with a plurality of radio receivers so that a computer can, by triangulation of the intensities of the various receivers, locate the landing spot for a golf ball emitting the pertinent radio signals.
Relatively large targets, such as automobiles respond better to the traditional radar systems. Moreover, a golf ball containing significant mass of transmitter, tagging components, capacitors, etc. has flight characteristics which are dysfunctional. Although radio wave technology for locating a lost golf ball has offered a variety of suggestions in patent literature, very few golfers have located lost golf balls using radio waves. The problem of locating lost golf balls has persisted. Around the world, the number of golf balls manufactured, has continued to be significant through the decades, thus accentuating the long-standing-need for a system for retrieving a temporarily lost golf ball.
Similar problems occur with croquet balls and other sports paraphernalia. Model airplanes and creatures are sometimes temporarily lost, and are retrievable using the apparatus and method of the present invention.
Baker U.S. Pat. No. 5,370,387 applies a fluorescent coating on a golf ball and locates it with a lamp emitting ultra-violet light.
Digital pulses of laser beams having a wavelength of 1310 nm are suitable for optical wireless systems over distances of a few kilometers, according to Heatley et al, IWWW Communications magazine, December 1998, pp 72-82. Such direct line communication by laser beams has selected advantages over radio transmission, including privacy, difficulty of jamming, etc.
Not only in communication systems but in any long distance use of laser beams, there has been the long term recognition of the desirability of using one of the three “window” generally referred to as laser bean having an explicit wave length selected from the atmospheric-penetrating group consisting of 880 nm, 1310 nm, and 1550 nm. One advantage of such atmospheric penetrating laser beams is that they can travel long distances.
It has long been known that gratings could selectively reflect light within a very narrow range of wavelengths, and such gratings have been used in some selected retroreflectivity investigations.
The retroreflectivity of arrays of glass micro-reflectors has been much studied, primarily in connection with the retroreflectivity of the headlights of a vehicle. Varnishes, enamels, paints, etc. containing glass microreflectors have been much used to reflect the headlights of automobiles. Tapes featuring such arrays of microreflectors have been widely used. One brand of such reflective tape is marketed by MMM as Scotchguard reflector tape. The evolution of retroreflectivity technology has been significantly generic, although certain innovations concerned glass bead paints, and/or glass bead tapes, and/or partially embedded glass beads, and/or other types of arrays of glass beads.
Cube-corner microreflectors, prism microreflectors, and spherical microreflectors and other types of microreflectors have been generically called glass beads even though reflective glass microbeads might be more precise.
Various reflectometers have been used to measure such reflectivity of road marking featuring glass beads. In order to measure such reflectivity during daylight while a vehicle is travelling at traffic speeds, a laser beam can be employed to measure the retroreflectivity of the glass beads. As explained by Perrin et al at Road Management and Engineering Journal, September, 1998, pp 1-8, highway maintenance engineers employ laser reflectometers such as the Laserlux device for this purpose.
In the parent and grandparent application, a laser beam having an explicit wave length selected from the atmospheric-penetrating group consisting of 880 nm, 1310 nm, and 1550 nm is employed to seek to retrieve a lost item having a badge retroreflecting such laser beam, and monitoring the signal generated by such retroreflected light. For example a grating can be molded into the dimples of a golf ball, thereby making it feasible to use a monitoring device to search for a temporarily lost golf ball. Such a monitoring device would also be useful in searching for a lost lamb or other critter wearing a badge responsive to the laser beam.